The Department of Meteorology noted that the low-level atmospheric disturbance near Sri Lanka is likely to develop into a low-pressure area around 11 May.
Showers or thundershowers are expected at most places across the island over the next few days, with cloudy skies prevailing.
Heavy rainfall above 100 mm is likely in parts of the Western, Sabaragamuwa, Central, Southern, Uva, North-Western and Northern provinces, and in Anuradhapura District.
The public has been requested to take precautions against strong winds and lightning during thundershowers.